Hey Brad,
To answer your question directly, NO. Unfortunately, there are no commercially available GP10s, or any other rebuilt Geeps in N-scale, for that matter.
The problem is that there are numerous different ways that Geeps were rebuilt, and different rebuilders called them different things, like GP7R, GP8, GP16, GP10, etc.. And what one rebuilder called a GP10 was different from what another called a GP10, which may explain why the LHS got him the wrong loco when he asked for a "GP10".
Whether or not there is something close depends on how accurate you want to be, and how much work you want to do yourself.
The only commercially available Geep with a low nose is a GP20, as seen here:
http://www.walthers.com/exec/productinfo/433-7790. But that model's nose is slanted, the fans are wrong, the exhaust ports are wrong, the grilles are different, and the gas tank is different.
That engine can be kitbashed from an Atlas GP7. The basic steps would be to notch the metal frame slightly in the front. Cut a section out of the front hood to make the "chopped nose" (my method for a slightly different version can be seen here:
http://home.att.net/~jcschuknecht/e28/bc-CL4611.html). Get an SD26 cab from the Atlas online parts catalog. Get the air intake detail piece (the part that sticks out on top of the long hood). You can get pieces to add the headlights, and too other minor details if you desire.
---jps
EDIT: Of course, I was writing this out while Squidbait posted his, hence the duplication.