FT - I have built one biplane from scratch, have rebuilt a vintage taildragger, currently have another scratch build bipe on the go and am rebuilding another for a mate.
Looked very closely at the Velocity during a visit to Oshkosh back in '99 as a septic friend, who came with me, was very keen to build one. On the whole I was very impressed.
I guess that your first move would be to contact both the PFA and the Irish equivalent and see what they think. I do not believe that it currently exists on the PFA list of approved designs but that may only be because until very recently, 4-seaters were not being approved and perhaps no one has shown any interest in the Velocity since the seating rule changed about 2 years ago.
Your second move really is to decide whether or not you can commit the time, energy and possess sufficient tenacity to see it to completion.
You have no idea how much work there is in building an aeroplane!
Stik