Non compete clauses are only enforceable if you are working for a company (selling lift trucks out of two baskets) but if you leave on your own or fired they are not. Legally, you can't deprive a person of making a living.

I think there's some truth to what you're hearing, and there's also a bit of exaggeration... as in most cases.
For instance, they don't "all" have non-competes. I would guess that the Hyundai/Nissan/Komatsu dealer does not have a non-compete requirement and neither does the Mitsubishi/Cat/Clark dealer. Neither do the Raymond or Crown dealer, to my knowledge but I may be wrong about that.
I've never worked directly for, but certainly at times I've worked with many smaller dealers that had very little inventory to work with. And again, as with most things - you find ways to work around it.
And what of the fact that they focus on rental business? Will you be paid to "sell" rentals? I would assume so.
There's a lot of ways to move iron in our industry, and a variety of methods to help customers acquire equipment... whether it's a LTR, STR, Lease, etc - if you're a long time veteran, I would think you would be able to find a way to get it done.
What specific Southeast/FL market are you looking to live and work in? I may be able to assist with that.