The biggest loose end appears to be CEO Ed Whitacre's desire for a $5 billion line of credit. Four banks have pledged $2 billion so far, with the balance expected to be wrapped up in a fortnight. The funds could pay for expansion plans and, more importantly, serve as a buffer in case the recession does the double-dip that's being increasingly discussed in economic circles. The Reuters report didn't mention anything about Whitacre's stated aim of restarting a captive finance arm before an IPO.
A $15 to $20 billion offering is still the range being quoted for GM's IPO. It is speculated that GM is so committed to getting things done this year that the company will lower the valuation rather than postpone the proceedings. There are still so many what-ifs and concerned parties involved, however, that it's looking more and more likely that we won't know how well GM's IPO will really do until we know how it actually did.