Re: Your build on a $1000 budget?
If it were for reliable transportation as my only transport to a job I depended on... I'd think very seriously about a new 2 speed Tomos moped. I don't have one, but they are made in Europe, have front & rear suspension, legal at 50cc, yet capable of mid thirties to 40 mph. I understand that they currently sell for roughly $1200.00.
I like to build my bikes, but I have the luxury of taking as long as I want to get it the way I want.
Racie's suggestion of a used Whizzer is also a good option.
If it's for getting to work, you want something you can depend on.
Someday when I grow up I will probably lose interest in toys with wheels, but until then...