AFAIK, this is the amp (with custom DSP parameters) that the RBH is using:
http://www.speakerpower.net/store/p27/SP1-2400-HT.html
So yes, that's a pretty big jump in cost IMHO.
RBH and Seaton are different animals (vented vs sealed), but the Seaton's are using a reasonably well proven driver (
measurements here), and the F18 system is such that you can buy a single master unit ($2,400 USD) and add up to 3 slave units for $1,200 a pop, so scaling your system up becomes easier.
For a more direct competitor, something like the JTR Captivator 1400 comes to mind (
measurements here), which can be purchased in custom finishes.
Last but not least, I'd also suggest contacting
Funk Audio, given that they're Canadian and also produce top tier equipment.