Depends on the project. For banks it's less likely that you'll be able to do something remote, but for telcos it's less of a problem as they rely less on security by obscurity and both use and give back to Open Source projects a lot.
Also the financial sector doesn't consist only of banks, there are many well funded areas one could work for remotely.
Also the financial sector doesn't consist only of banks, there are many well funded areas one could work for remotely.