It won't have much of an effect on miniPod sales, since demand has way outstripped supply for iPod minis.
The new units will probably be in 20, 40 and 60 GB sizes, mainly since Toshiba announced their 60GB drives several months back and claimed Apple was a customer.
The latest rumours included a sleeker design, closer to the miniPod form factor than previous models of iPods, and boast several colours. But unconfirmed as to which colours...