If you think the P11 is bad, try the P3AT! The PF-9 isn't great fun, either, but the trigger is much, much better.
(I spoke with Kel-Tec a while back, and a rep there said that they will probably, eventually, introduce a P-11 with the PF-9 trigger, and if they do that I'll get the new version of the P-11. The trigger was a turnoff for me.)
I've found that the grip material offered by KTADDONS does make the shooting experience a bit more pleasant, and it's not all that expensive. I've used the the KTADDONS on a P3AT, on the similar LCP, and on m7 PF9, and liked it...
http://www.ktaddons.com
As I was getting ready to post this response, I tried the link above, and it didn't work. I don't know if that's a temporary problem, or they've gone out of business.
Another source suggested using strips of a Dr. Scholls shoe insert, cut to fit the front and back straps of the gun, with a Hogue Handall Grip slipped over them to hold them in place. That might work as well. (I'd probably try gluing the, or using two-sided tape to position them before trying to install the Handall...
A little extra cushioning and maybe some extra girth (wrapping the strips around the side of the grips, perhaps) would spread the recoil over a larger area of the hand, and a bit of the force would be cushioned/absorbed by the material.