Bitshare itself might be interesting, if it allowed integration with bitcoin blockchain. But it just seems to be yet another altcoin (but at least innovative). Without bitcoin though, you'll have hard time beating OT as it shares same problem as you - lack of momentum to peg on.
This is where something like Marketcoin is very useful, quick trustless exchange of value between chains means altchains only need one function (like a zerocoin altchain or a bitshares altchain) in order to be useful. We should function on creating functional, innovative coins instead of trying to cram everything into Bitcoin. Bitcoin is wonderful, but it is designed as money and I think it would be good to keep it that way. The entire point of open source is that if someone want's to improve or alter Bitcoin they can.
Which is why altcoins are interesting for research, but not in foreseeable practice - what I am saying get *something* useable in bitcoin, get people hooked, once scalability issues inevitably show up, transition to altchain.
Crosschain p2ptrade is actually easy problem if your altchain is designed to support it. Only place where you hit the blocks is things like
direct LTC x BTC without established altchain proxy supporting cross-chain p2ptrade.
Cryptocurrency design is not just code alone, but common market patterns (greed/fear) as well, otherwise you end up with another chicken-egg schizm nobody wants to use because nobody uses it thus cannot be trusted.