If anyone is interested, I've developed a foreign data wrapper that can be used to connect to Sybase databases and Microsoft SQL Server. You can get it on GitHub here:
I did my testing with FreeTDS, an open source TDS library.
I've talked to Greg Smith about this in the past. I don't really have the expertise or resources to develop and test this much more than I already have. If anyone likes it and would like to take over "ownership" of the code, feel free to do so.
I actually developed this over a year ago, so it doesn't support write operations added in PostgreSQL 9.3.
By the way, thanks to everyone who spoke at PGConf NYC 2014. It was very informative.
Geoff Montee