Hello!
While I generally don't use frontends, I find your project very appealing, especially for the bundled games feature, which IMO must be helping a lot to bring DOS games to a wider audience (taking into account that not everyone is willing to mess around with DOSBox settings on their own).
Anyway, I'd like to throw in a couple of suggestions regarding free - or rather, liberated - DOS games.
First off, as you probably know,recently the full version of Amulets & Armor has been released. It is my understanding that one requires a permission from the team to host and distribute the classic version, but if they give the permission I think it'd be an awesome addition (even though the shareware version is already included in one of the bundles).
A seemingly much less known game is Legend of the Silver Talisman, the full version of which is available from the developer's website.
Battles of Destiny is a sci-fi turn-based strategy from Holistic Design, which had also been released as a free download (maybe you need to ask permission to host this one too, I'm not sure what the license says).
One of the bundles includes Sango Fighter, and there is yet another, somewhat related game the rights to which had been also obtained by the Super Fighter Team, namely Super Fighter, which is also free.