The indie snap! matte box is a great little affordable matte box kit. It’s a very well made matte box with french flag and available side flags, for just $189!

It can hold 84mm filters, and fits the following cameras:
“DVX100, DVX100A, DVX100B, AG-EZ1, Canon XL1, Canon XL1a, Canon XL2, Canon GL1, Canon GL2, Sony VX2000, Sony VX2100, Sony PD150, Sony PD170, Sony FX1, Sony Z1, etc….”

Discussion at this DVXuser thread.