why not go for something finance/trading related since you're into that anyway? banks pay silly amounts for contractors and lots of them are pants.
if they're funny about finance experience then maybe try some smaller buy side firms - hedge funds, proprietary trading firms, options market makers etc...- while some of these will want people with esoteric skill sets for ridiculously low latency stuff other firms might well be using Java etc...
http://marketcetera.org/ is open source and perhaps worth taking a look at
there are some open source FIX applications too
am sure there will be some smaller firms out there who are prepared to pay a fairly decent rate to someone who can simply get stuff done with no fuss...
