Aha--I suspected as much. The answer appears to be "no." Aside from a tiny few high-profile, national Republicans such as Chuck Hagel or Susan Eisenhower, there aren't many "Obamacans"...and I sure haven't come across many ordinary Republicans going for Obama in my readings or travels.
Here's a quote from the linked article above:
"But are there enough rank-and-file Republicans whispering their support at Obama rallies to actually make a difference on Election Day? As I discovered from examination the last 18 months of head-to-head general election polls, the answer seems to be "no." In fact, John McCain's share of the Democratic vote has typically--and surprisingly--been larger than Obama's share of the Republican vote. In other words, it's not that the Rev. Jeremiah Wright scared the Obamacan masses off, as some pundits have theorized--it's that they never existed (in any unprecedented way) to begin with."
Read the whole thing--he presents solid evidence to back up his claim.
Or, put it this way--if one is going to write about Obama Republicans, it would be equally as valid to write about McCain Democrats--there are at least as many of them.