Do your really want a Spey rod or would a switch rod be a better choice for your needs??

Both are two handed rods, the spey rod is slightly shorter - about 10=1/2 feet so really like a single handed rod but you can use either one hand or two hands as the need arises. The spey rod will be longer and pretty much only casts with the appropriate 2 handed techniques.

As for blanks, look at Batson, Meisner, Dan Crafts, forecast, as well as the propietary companies like Sage and G. Loomis.

If this is your first build ever, you might want to start with an inexpensive kit to get the basics down before you go to the expense of a mediocre first build result.