Well after a bit of research I'm somewhat settled on a Soma Van Ness as the frame for a SS build.

Unfortunately, I don't know much about this type of bike. Based on what I know it's more a FG bike but they sell it as a SS as well. What do I need to know to build this as a SS? Will a normal SS hub work fine (120mm spacing)? Crank, brakes of my choice okay? Any suggestions? Keeping in mind my hope to keep the build in the $1,000-1,200 range (I have a saddle, bars, stem (threadless), seat post, pedals already).

Thanks.

Go back to your link and read the FAQ. You will find your answers there. There is no difference between a FG and SS frame, other than some conveniences like cable housing stops on the top tube for a rear brake. Also, that frame is meant for road riding rather than track with better tire clearances and multiple bottle bosses etc.

Thanks for the info. Those are the reasons I chose this frame over some others, but the rear facing drops have me confused. Based on other feedback I received here the rear facing drops are less ideal for SS, due to getting the brake set up right, but apparently not impossible. I guess I'm just wondering if there are possible gotchas that I should be aware of before ordering parts.

Correct, track dropouts are less convenient than forward facing semi-horizontal dropouts. However, if you don't change your gearing then your rear wheel won't need to be moved in the dropout and the brake pad position will only have to be adjusted once. Another convenience of the forward facing dropouts is that it is easier to install and remove the wheel, particularly with full fenders, and they typically include adjustment screws so proper wheel alignment and chain tension is maintained. If you decide to get the Van Ness, you might consider getting a Surly tug nut to make the adjustment process easier as well as protecting the paint on the dropout.