Hey Matt! Welcome to the forum and to the world of bonsai. It's so awesome to see that you're taking the time to research first...that's not what I did and I regret it.
As for maples, South Caroline should be an awesome climate for them. As for what grows faster, that really depends on the species. I've made maples my priority at this point, but I've got a variety of things growing. I know Tridents are very vigorous growers, and growing in your area will definitely help you out -- longer growing seasons. Depending on the cultivar of Japanese maple, some are very fast growers and others are not. You'll see the difference with dwarf varieties -- they grow quite slow. As for starter trees, I'll list several-ish places, but I've only purchased through a few of them.
First, I don't know if Treekutter (a member of the forum) is still selling his Tridents right now. I know he has a field full of them that have been growing for quite some time, but digging season is up now, I'm sure. He may have some potted, though, so it's worth a shot.
Here's a link of some of his recently dug material. You can always shoot him a message to see if he's got anything for you. My experience with Steve has been very positive --
the tree I received could have easily gone for twice the price he sold it to me for.
There is also Evergreen Gardenworks -- run by Brent Walston, who you may see posting on here from time to time. He's got tons of stuff growing all the time, and he offers a lot of different cultivars. He also has a "specimen" page where he's got several Japanese black pines and Corkbark elms posted, but these are a bit more expensive than starter material. Here's his website. He's a very nice guy, and I highly suggest him.
I've heard great things about
Telperion Farms (I think that's how you spell it. . . .). I've never purchased anything from them myself, but I've seen some of what they have to offer and it looks like great material. They also have a blog, but I can't seem to find it right now.
Matt from Kaede Bonsai-en is an awesome guy and sells several hundred seedlings each year.
Here's his site. I just received an order from him today, in fact. He's extremely helpful and he's got a lot of smaller stuff to offer -- Trident, Japanese maples, pines, quinces, etc.
I've also seen
Wee Tree becoming much more popular as of late. They offer a lot of very well developed material. I've never purchased anything from them, but I think Judy B has and she was very pleased with it. Check out some of their stuff as well.
George from
Muranaka Bonsai offers Trident maples frequently on his eBay store. They're definitely worth checking out as well. I've never bought anything from him, but I've talked to George and he's a very nice guy.
Oh yeah, how on earth could I have forgotten Don Blackmond from
Gregory Beach Bonsai??? Thanks, Judy, for reminding me. lol -- He's got a ton of advanced material for great prices.
Here's a tree I got from him recently. Definitely check his site out as well.
*Edit - I forgot about
International Bonsai as well. William Valavanis offers a wide variety of seedlings and pre-bonsai. I've gotten some flowering apricots from him before. Great material at a very reasonable price. Also worth checking out -- make sure not to overlook the catalog link on that page.
And for what it's worth, you might not be worried about wiring anything just yet, but if you do,
Adams' Bonsai is the place to go. They've got annealed copper wire and the best prices I've seen.
Enjoy your search!