I can get them through my distributor yes. Right now there is still a limited supply.
A larger diameter will have more traction but is also like using a taller gear so it may slow you down a tad. They do make 26 x 8 and 26 x10" tires.
I would use a M/T or Hoosier.
Would you want DOT or non DOT?
I use a M/T 275X Pro DOT Drag Radial, but that might be a little too wide for you.
Currently they have 1 pair of these in stock in 26" diameter...
#90000024091 by MICKEY THOMPSON
Tire, ET Drag Pro, 26.0 x 8.5R-15, Radial
ET Drag® Pro Drag Radial
www.mickeythompsontires.com
I used to have 4 back wheels and I would just swap my stickies on before I drove to the track and then put the street tires back on all the other times.
With the new setup I don't bother with street tires as they are nearly worthless.
I do think it might be in your best interest to install the stronger axles before you bolt on the stickies.