Congratulations on the sale, genjamon. Sometimes a lot depends on how patient you are, plus it's just after Christmas and a lots of folks still have empty wallets. I think your pricing was reasonable.
The 50% rule may apply to regular commercial products, but I believe the NCores are different (as DIY projects) as apparently is the Job that's also mentioned here. I may have to eat these words if I ever wish to sell mine, but these are outstanding amps for such little money -- just look at what the commercial (more powerful and refined) NCores are going for -- and they're getting great reviews.
Value of course is always in the eye of the beholder. I purchased a used pair of NCores last year, with the Kraemer (Aluminati) cases and paid double your asking price. Maybe I should have haggled with the seller, but what can I say -- I liked the cases. For $2800, I can't think of a pair of amps I'd rather own, new or used. I buy 90% of my audio used, but this is different. You have to compare it to what else is available at the same price. If these NCores were being sold through commercial vendors, they'd cost a lot more, and this needs to be figured into the equation. These aren't for everyone (They're not tube amps, or even Class A) and some shy away from non-commercial models, but some of us appreciate the extra value.
I think these are good times for audiophiles, where top (well, close to top) performance can be had without breaking the bank, esp. with amps and DACs (love the BMC PureDac paired with the NCore). Hope you like your TRL....