oppro: i came up with the shape because i really like the look of single cuts, and you tend to see them mostly on basses unfortunately, so i thought that because an 8 string is getting near bass territory, that it'd be appropriate :) Sustain should be good, as i'm really happy with the neck join- even without the bolts, it's a very good, snug fit... time will tell though, but i'm hopeful at the moment.
Roo: this instrument isn't going to be multiscale i'm afraid, it'll be a standard 28"- when i bought the bridge, I hadn't considered it as a fanned 8 string bridge (or 8 individual saddles), would be prohibitively expensive for me at the moment. I'll leave the 1st multiscale on this forum to Philosoful, but our other fanned-fret ambassador (WesV) is planning a multiscale 8 at some point, so keep your eyes peeled! :)
Philosoful: Fretboards are radiused to provide more comfort, but radius suits different applications; a flatter radius suits playing (and bending) higher up the neck, whilst open chording and stuff lower on the fretboard suits a greater radius. Take a classical guitar and try and play some regular chorded stuff- it feels a bit weird because of the flat radius, but do some shredding on an old strat, and it'll seem a bit odd (don't tell Yngwie that though)... that's some pretty big generalisations there, but that's a very rough explanation.
Fanned-frets on the 7.... it was my first build, and i was very curious about multiscale, so i fancied giving it a shot, thankfully it paid off, and i'm loving the results. I've had really good positive feedback from everyone that has played it :) The fanned fret 7 is tuned to BEADGBe, and this 8 string will be the same, but with a low F# too. The neck join will have a little more taken off of it, it'll be fine for playing the higher frets... it's my first time of trying this style of neck construction with using ferrules and bolts instead of screws and a plate, so in a couple more builds hopefully i'll have it down much better.