Hi RL,
Congratulations on bringing the beast back to life! I'm jealous. I'm quite a ways from that point with my '62 TR4, which also languished in the garage for far too long! I can only dream about waking the neighbors at this point. But, at least it's much farther along than it was 6 months ago.
I'd also recommend sticking with the SU's as the best solution. Set up properly, they are hard to beat for a fun, daily driver.
An alternative is Hitachi SUs, which were used on Datsun 240Z (and some other cars). However, these can be pricier and more in demand than British SUs. Also, while they are essentially the same design and function, I would imagine there would be some tweaking and adapting to make them work. I can tell you my TR4 had a set of Hitachi SUs installed when I first bought it and I didn't even realize until recently what they were and that they weren't original to the car. It ran fine, but has since been modified a wee bit and now uses a pair of Weber DCOEs.
Speaking of Webers, there are two major types: downdraft and sidedraft. Sounds like the pricier, high performance oriented sidedraft (DCOE) aren't what you are looking for. They really demand a lot of other engine work and tuning to make them work as best possible (increased compression, porting & valve work, headers, free flow exhaust) so the cost of the carbs is just the proverbial "tip of the iceberg".
Many of the downdraft variety Webers are more reliability/economy oriented (although there are performance downdraft versions, too). These tend to be less expensive and might be a solution, if you don't mind a non-original setup.
But, I still think the SUs are hard to beat and pretty easy to work with. If you do decide to stick with SUs, there are rebuilders/reconditioners out there, and parts are pretty easy to come by if you want to do the work yourself. The only concern is getting a "correct" set. There are a great many different models of SUs, sometimes with very subtle differences. You might find a metal tab on the float bowl of your carbs with the model numbers, for reference, or a shop manual would tell you the correct models.
All sorts of SUs show up on eBay all the time, so that might be a good source. Only the later HS6 SUs (TR4A) seem to be available new and are pretty pricey.
A final consideration, if you stick with SUs you will likely be enhancing your car's value, while any non-original change will likely devalue it to some degree.
Cheers!
Alan