You could do like several of the fellows in our club did. When they decided they were ready for a tail dragger, they converted their trainer.

Big advantage is that you are real familiar with the plane. Another plus is that converting the trainer is dirt simple. If the main landing gear is wire type, buy a strap type landing gear and a tail wheel.

Fit a piece of aircraft ply, 3/16 inch thick or so in the fuselage bottom. Situate this so that when you screw the landing gear on, the axles will be in line with the leading edge of the wing.

Use blind nuts in the plywood and screw the landing gear into this with nylon bolts. - this way, if you mess up a landing, you shear the nylon bolts and don't pull the plywood out of the bottom of the fuselage.

Another advantage is that now you have a trainer that doesn't look like every other trainer at the field.

Hopes this helps to give you another alternate.