Acrylic lacquer is your best option. Duplicolor makes a filler/primer that you can use along with their Truck, Van, & SUV colors for $6/can. You can use their clear coat lacquer also, but I like to use Spray Max 2K urethane clear instead for under $20/can at http://www.repaintsupply.com/pd_2_part_2k_aerosol.cfm
Just finished a guitar project using Duplicolor and Spray Max...
[youtube=425,350]http://www.youtube.com/watch?v=qwws6f0r2iw[/youtube]