Shapeshift.io just added XMR support and it looks like the database is one step closer. Development wise it looks like there are good things on the horizon.
Shapeshift announcement:
https://twitter.com/ShapeShift_io/status/585570515139563521
Pull request to merge database into master:
https://github.com/monero-project/bitmonero/pull/256
Timing-wise there are potential issues with that
1.123 BTC -> XMR -> 1.122 BTC over a short period of time might be fairly obvious. Of course it depends not the amounts and the level of activity on BTC at the time. If BTC has 1000 tx/sec that would be a lot more obscure than currently
So clearly the solution is to go 5 BTC -> XMR -> 1.22 BTC.
( XMR go.... to... alpha... centauri....)