I went through a similar thing to you, but from a different angle - a late starter who wanted to go shorter but stay high volume as I dont get in the water enough to go too short (and am old and fairly big - about 85kg). I ended up with a custom board, but there are a few board around mid-7ft that I reckon you could give a go. So here is my blather from what I found in my research...
The first thing to think about is whether you want a mini mal shape (rounded nose and straight rails) or more a hybrid shape (pointer nose with rounded egg shape). The former is easier to surf but the latter is more manouverable.
(by the way, when I mention boards in this comment, I'm mentioning boards for the purporse of further research and which are available to look at on the web, not because I mean these exact boards ie just so you can get an idea. However, some of the boards are widely available if you want to buy off the rack; if you want to get a shaped board then they are a good research tool to start your shaping discussion)
In the mini mal category there are boards like the Walden mini mega magic (quite high volume - check out the 7ft 6, massive 74l volume). There are obviously other mini mal shapers and makes around which do much the same job (but perhaps not quite the same volume).
If you are intersted in the minimal shape/type of board, I suggest looking for a board that has a fairly pulled in tail (eg my board, which is is here
viewtopic.php?f=20&t=15393&start=280 about 1/2 way down, you can't miss the colours... anyway, rounded nose, wide, flat rocker, fairly thick, pulled in tail and, although you cant really see it from the photos, quite hard rails towards the tail). The Takayama scorpion is another model even more radical; although its probably too small for you but you can see the nature of the outline I am talking about. The McTavish Carver and even his Eightball are other options (
http://www.mctavish.com.au/surfboards-buy/midlength) which are probably lower volume. I'm sure most good longboard makers will have something similar in their line up.
The second category is the hybrid shape, and again there are a couple of boards worth looking at to start off with. The Firewire Addvance is a big fat hybrid board that appears to fit the bill, as does the 7S Superfish. The Superfish gets a lot of good comments and its a board that might be worth a good look for you given that you do have a skilled background in surfing; the Addvance is popular as well and I was very close to getting it myself. Again these boards have fairly low rocker, are wide and thick. They are probably 'higher' performance than the mini mal shapes, but as mentioned probably not quite as easy to surf.
A left field choice could be something like the Mccoy Nugget, which is a fairly unique board but some people love it. I'm not sure how available they are in the USA tho.
Anyway, if you have made it this far, I've thrown a few board names around. Basically there are the mini mals but you want one that are a bit thicker than normal, flatter rocker and higher performance than the standard NSP style mini mals. These are, I guess, shorter long boards, essentially, but retaining volume and made with some thought rather than just cutting 2ft off a longboard. And then there are the long hybrids/fish, which are more like longer shortboards.
Finally, the guy who shaped my board is unfortunately no where near you, but he specialises in higher volume boards for the bigger/older guys, so his website is worth a look. Its a bit hyperbolic, but his board shapes and dimensions will be useful as part of your research -check out here
http://www.grantmillersurfboards.com.au/ You will see the 'performance' mini mal (the Powerglide, the one I have) and his version of the 'hybrid' board (the Waterskate). A board like either of these, in the mid 7ft area, I reckon will do you perfectly.
Good luck - board searching is fun and frustrating; but there are definitely options out there for you.