Hmm, I guess the main draw of Flirc is not needing software installed to use it (other than initial programming it) so a solution that would allow you to control different things would have to be coded within Flirc module.
(e.g. XBMC preset: Play on remote = p
Powerpoint preset: Play on remote = F5 (or whatever starts a slideshow))
Also I believe Flirc can only store 160 keys, I say only but if you had several presets then it may get used up.
But as the idea goes I think it is a good one - you could use the colour buttons on your remote (I don't use them) to switch presets:
Red = switch to XBMC preset
Blue = switch to powerpoint
Green = switch to windows media player
Certainly an idea to entertain... how easy it is to implement - I have no idea.
Pleasant regards,
Chris!