low budget boards often don`t, if you have any sort of skill with tools you can cut a new one from an old biscuit tin or something with scissors (old ones....use mums best ones and you might be grounded for a year or so) and drill holes for the connector stud thingys, just be carefull when you do it, raw cut tin is SHARP and treacherous...wear gloves if possible.
often the backplate comes with the case, in the case of my AMD machine I just modified the old plate since the new board had more connectors than the old one and I needed the existing cutouts plus some more above them, for lower spec machines you could just leave out the plate anyway, cooling isn`t so critical and the plates primary function is to stop air going in where it shouldn`t, it`s secondary job is to provide screening for the connectors, but I didn`t notice any problems when I used a plastic (non conducting) plate (I was fresh out of biscuit tins
)
Mentor.
PC1: P4 3ghz, 1gig mem, 3x160gig hd`s, Radeon 9800pro w cooler (3rd gfx card), 6 way speakers.
PC2: AMD 2ghz, 512mb ram, FX5200 ultra, 16 bit SB.
Mini ATX cases suck.