If sometimes you need to just create your own font... well maybe that's a bit too much theoretical - but it's interesting to play with a tool like VOLT. It's out now in a new Version and I suggest taking a look:

"The Microsoft Visual OpenType Layout Tool provides an easy-to-use graphical user interface to add OpenType layout tables to fonts with TrueType outlines. It is licensed free and can be downloaded from the online community set up for it. The community hosts an active discussion forum, version history information, a wish-list and related downloads. Links to VOLT's release notes, as well as tips and tutorials are also posted."

Source: http://www.microsoft.com/typography/VOLT.mspx