I've been looking at doing the same thing, so here's some additional info... hope it's helpful.
The 2003 'Bota hoes are the BH90 and the 4690. BH90 is a 9' subframe unit that competes with the Woods 9000. Runs on tractor hydraulics. Won't fit on the Grand L 10 series... only goes on new L 30's. Kubota still sells the prior model subframe hoe for the L 10's, but the price is prohibitive... my dealer mentioned $8500+ before I changed the subject.
4690 is a continuing model, a 7 1/2' 3pt unit that competes with the Woods 7500, and fits both the L10's and L30's. Has its own PTO-driven hydraulics. Runs something like $6000. Regardless of whether you go Kubota or other, if you get a 3pt hoe, be sure to get a reinforced toplink bracket.
Even though the 7 1/2' hoes are a bit undersized for your 3710 or my 4610, I have kind of settled on the 4690 for my amateur use. If the application were commercial, the 9-footer would make more sense. I favor staying with the factory unit for a 3pt hoe, rather than one that is generically designed and adapted to different tractor platforms. Woods does make excellent equipment... their 9000 is probably my second choice. You can get it configured as a subframe, pto-driven model, a combination Kubota does not offer (and you can order it painted orange!).