Thinking about this last night - why would it take longer to solo with a tailwheel? The pattern is pretty much the same no matter which end of the airplane has the third wheel. Some of the common tailwheel aircraft are a bit simpler to operate without flaps or mixture, so getting the routine down would be even easier.
Final - doesn't matter if the tailwheel is on the right or wrong end. The trick is to learn to judge the angles and aiming point. And, again, if you don't have flaps, that's one less complication. But, on the other hand, it seems that the tendency with flaps is to just put them down and drag it in with power to undo the drag from the flaps.
Flare / judging height above runway. This seems to be where students struggle the most. And, again, no difference. OK, in some aircraft the runway tends to disappear at this point which would make things more difficult, but in the common tailwheel "trainer" aircraft that I have flown - T-cart, Cessna 120, Citibria, Champ this is a non-issue.
The traditional exercise of flying the length of the runway at 1 foot or so is the same as well.
So at this point, we have made it down to 1 foot above the runway, and through most of what students find hard without any real difference strictly due to the location of the third wheel. So, I would not expect any difference in the time to learn this sort of thing.
Touchdown. In theory, the nose of the airplane should be pointed in the direction of travel as you touch down (with a couple of exceptions). In most tailwheel aircraft you quickly learn there is an alignment between theory and practice. In many nosweheel aircraft the theory can be regarded as a bit more theoretical - it doesn't really matter if you are straight or not. If you land all catywompus, it will fix itself even if you have your feet on the floor. So this exercises is easier with a nosewheel, but by the time you get to where you can flare with flair, your feet will have figured out how to keep the airplane pointed in the right direction if necessary.
Rollout. You have to pay attention if you are flying a tailwheel aircraft. Not a good time to go head down and start playing with flaps, mixture, radios, whatever. You can't steer by turning the yoke (unlike some nosewheel aircraft that have a bungee between ailerons and rudder). So, it is more difficult than just sitting there waiting for the turnoff so you can pick you feet up off the floor and make the turn. But, if you learn from scratch, you feet don't realize that they are being made to work harder than in other aircraft -by the time you figure out how to flare and touch down, this part is second nature.
Takeoff - again the only difference is that you actually have to have your head outside the cockpit and your feet in the game. You will figure this out during the first lesson. If the instructor insists that you watch the airspeed / engine instruments as you trundle down the runway you will have a harder time but quickly you learn to limit your attention to the panel to quick glances at the most.
Air work. Some aircraft have a lot of adverse yaw. This tendency seems to have some correlation to the location of the tailwheel - but not always. In the aircraft with adverse yaw, you quickly learn that the pedals are not just foot rests. And, as an ab-intro student your feet don't know that "it's not fair" and stuff just happens.
So, would it make sense that it would take longer to solo in a tailwheel aircraft? I think not.