Also, OPer
Campyoldy sometimes has a nisi 40holer I think. 700. You haven't stated what size you're going for, but assuming 700 as you're going to have trouble finding a front tyre that'll fit if 27".
BUT
You should just use tubs. Sounds like the frame was made for them.
Or 26 rims and give yourself some more tyre clearance.
Also, OPer
Campyoldy sometimes has a nisi 40holer I think. 700. You haven't stated what size you're going for, but assuming 700 as you're going to have trouble finding a front tyre that'll fit if 27".
BUT
You should just use tubs. Sounds like the frame was made for them.
Or 26 rims and give yourself some more tyre clearance.