The current one does 16 Gb.
And remember, the next one is due in 2013, so that is a long wait.
And there won't be quad Ivy's, and there won't be dedicated GPU's.
The mini is gonna shrink because of Ivy, instead of improving performance. The current one is too expensive to ship and to mill with all the hollow room inside.
Expect a 12x12x3 to 15x15x3 cm dual core i7 with 3 USB 3 ports, 2 TB ports, an AC port, an audio port, 256Gb SSD, 4Gb soldered RAM, with BTO option to expand to 16Gb.
If that is not your like, buy the current i5 Radeon one as it is in discount very often nowadays for close to base model prizes.