Would it not be better to just get a used 5M SLE kite with standard bar? There are some on ikitesurf for sale (assuming they are still available).
It seems like it would be best to get something that is as close as possible to "the real thing". It could also be taken out to body drag in the water and could be used to drag a kayak or tube.
I like the idea of the HQ Hydra that The Captain suggested as well. If I had to do it over again, I would not purchase a 2-line 2m trainer kite, but I think one of these kites would be good and could be used for other purposes.
I agree. If I had to do it all over again I'd buy a small c-kite or SLE kite. It would save time and be just as safe if not safer. I've seen a couple beginners get thrown by 'trainer' kites. I learned with a good quality 3.6m trainer kite and was not disappointed but I think my progress would have been a lot faster with a small sle or c-kite. You'd be training with the same style kite you would eventually use in the water. You'd be familiar with re-launching, the safety etc. Most foil type trainers for 300 bucks don't have the same safety and depower and relaunch differently than your typical water kite.
You can still use that small kite on the snow in stronger winds. But the trainer you'll never use again once you move to the big kite.
Food for thought I guess.