RosenMcStern
Mongoose
andyl said:Some of the other BRP settings may require a bit more tweaking, or using non-RQ rules. For example Crusaders of the Amber Coast has its own magic rules but I would expect that they should just port over without a problem.
Actually, I used the CotAC campaign to playtest MRQ2 when both were still unpublished...

So yes, you can use the magic rules of MRQ2 very easily for CotAC. Just use MRQ Divine Magic (Pact = Piety) and Common Magic for Pagans. You can also use Deus Vult as a guideline for the Crusaders.
As for historical supplements not selling well... uhm, Rome won a prize this year. And ennies are not assigned by a jury (just the nominations are), so someone must have voted them on the net. You will find more fantasy than historical in the market, but historical settings are the ones where d100 traditionally fares better than d20. And the license is very cheap.