GSO make a low profile focuser, M-MLP230,
http://www.gs-telescope.com/content.asp?id=139
and it should fit your existing mounting holes. Most GSO dealers should carry it.
Also make sure you use a low profile T-adaptor such as FF145,
http://www.gs-telescope.com/content.asp?id=137
Also loosen the primary collimation screws first to the max and then re-collimate by tightening two.
If all that is still insufficient, move the mirror up the tube if possible. I'm not sure how the mirror cell is mounted but it's usually three screws at 120deg. just drill 3 new mounting holes provided you can slide the mirror cell up the tube. No need to cut the tube but you may need a slight re-balance. Of course if the mirror cell must go at the end then you may have to cut the tube but only after all other options have been tried first.
Note moving the mirror up by sliding the cell or cutting the tube will have an impact on the light cone and you may need a larger secondary mirror unless it is already oversized. (Although you may not notice the difference).
Note for visual use you will then need a 2" extension for your focuser, again GSO have three lengths to choose from and the shortest should suffice.