Both Clark County (Las Vegas) and Washoe County (Reno) provide a breakdown of early voting by party ID.  In the rest of the state, party ID is not given but the total early vote numbers are.  Also, voter registration is broken down by party. 

Using this data and assuming:

1. Independents break even.
2. Obama captures 90% of Dem and 10% Rep, and vice-versa for McCain
3. Early voting in the rest of the state is proportional to voter registration by party ID.

Crunching the numbers, I estimate Obama is ahead b 62,000 votes.  Up 76,000 in Clark and Washoe counties combined, and down 14,000 in the rest of the state.

There are approximately 233,00 Republicans and 252,000 Democrats who haven't voted.  If we assume that 90% of Republicans turnout on election day and all vote for McCain, this gives them an additional 210,000 votes.  This means that Democrats have to net 148,000 votes out of the 252,000 remaining Democrats.  This will happen is we turnout 75%, with a 90-10 Obama-McCain split.

The Bottom line; if Democrats turnout anywhere close to Republicans, we win.