Given both the difficulty and the amount of effort House Mercere has put into keeping the Gifted bloodline of the Founder alive, I would expect even unGifted Redcaps descended from the Founder to face significant social pressure to keep a paramour in every town they can manage.
Edit: On a related note, I would expect Mercere to keep several lab texts and/or casting tablets for InCo T:Bloodline spells and keep at least one competent Merinita on retainer to cast them occasionally, to track down any lost seeds born to barmaids or what have you. These would obviously also count as scrying on any currently-known-to-exist Redcaps of the bloodline in question, but by precedent regarding Frosty Breath of the Spoken Lie I believe the Redcaps in question could consent to the specific spell(s) in question- obviously they couldn't be forced, but the social pressure would be enormous and in any case the vast majority of them would be in favor of it anyway, if the House is running its indoctrinationsapprenticeships with anything remotely resembling competence.
My assumption has always been that they act only as middlemen. You pay your red cap (A+B+C) pawns of vis, they pocket A, give B as payement to a vis strapped mage (probably in a vis poor Tribunal like Normandy or Rome) who needs C pawns to make the item. Same as for the lab-text delivery system. They take a cut and pay someone to make their apprentice spend one season copying out a few lab-texts from their library.
That’s explicitly not how it works according to HoH:TL due toboth the fact that redcaps carry their own vis, some of which may be on loan from the house, and the bit about the vis banking.
Ah, there I assume it’s more they just deliver the messages, usually. But the library at Harco rivals Durenmar so I asume for books and lab texts they have most of the standard stuff covered within the house and the scribes with MT to boot.
I agree. It is my group's view that the Roman tribunal essentially earns their vis providing services. Since the number of Gifted Mercere is quite low, they would probably contract out, possibly calling for bids from their contractors. Send a redcap out to their regular "we need a level 33 ReCo item, how much will you charge" and pick whoever made the lowest offer.
I would not see them as receiving any Vis from the commissioning of magic items.
The back and forth is accomplished by letters, which the delivery of is part of their normal duties (for which they are gifted already). The delivery of small items also falls within the range of their normal duties (much the same as books). The transfer of Vis would be covered by their Vis banking. If the item is larger than the Redcaps will deliver or the enchantment must take place on site then the cost will be worked out between the parties, often in the same letter exchange as the commissioning takes place.
Now for common books and lab text which are contained within their House library at Harco, purchase of copies from the Redcaps (YSMV) would be common. Put in an order with a visiting Redcap, the cost is deducted from your Vis balance, and they deliver the text. Requiring that a Covenant have a Vis balance rather than payment on delivery is just one more way to encourage Magi and Covenants to use their Vis banking services. (This is very YSMV, depending on how common you wish to make the exchange and sale of books/text. If you want it low, then they do not engage in this at all. If you want it common, then they might actually distribute letters to all Covenants with their 'Text for sale' and the cost.)
I know that Venitor the Verditius is the right kind of specialist, so I send him a letter to make him an offer, and we negotiate, and the redcaps deliver as part of their usual service.
I need an item, but I do not know who can deliver at a fair price. Therefore I ask the redcaps to broker. With the combined contacts of the House of Mercere, they will almost certainly find one of the best offers available, and take broker's fee for the service.
I would not be surprised, either, if the house, or individual redcaps, have some minor, generally useful magic items in stock for sale. They could be second-hand items, pawn-broken items which have defaulted, or maybe even minor enchantments in high demand that have been commissioned. Anyway, for story purposes, such a peddlar in enchantments could be an interesting occasional character for flavour, but working it out as a mail order service breaks the feel of Mythic Europe for me.
There is one more caveat. I am sure it is mentioned in canon that redcaps charge extra to carry vis, at least in larger quantities, because it entails added risk. Enchantments come in the same category. Hence, while two magi may negotiate a trade by correspondence without paying extra to the redcaps, the dispatch of the enchantment might well cost extra postage and/or insurance. OTOH, I think canon says that such trades are normally completed in person.
