This strikes me as being Melanolestes... the tibiae seem expanded in some of these pics and the thorax is rather shiny

Yes, I believe this is a male Melanolestes picipes--males have long wings, females have just wing stubs. Compare such images as:

And I've seen the males flying around here at this time of spring in North Carolina--climate similar to Oklahoma.
Good point about the expanded tibiae and the shiny thorax, Joe--that looks to be correct. Compare Reduvius personatus:

Very similar in overall form, but again note the features of Melanolestes picipes that Joe notes above.

Any idea of what M. abdominalis and M. mono look like.. I'm always hesitant to put a species to a specimen without knowing the full diversity of the group

M. abdominalis has the abdomen (of males, anyway) outlined in red. Pretty distinctive. I did not even know of M. mono, so cannot comment there.

I believe that M. abdominalis is now considered a color morph of M. picipes--at least that's the way we wrote the guide page way back when. See comments under this image which is, incidentally, a short-winged female with red on the abdomen:

So are we going to go with Melanolestes picipes or Melanolestes abdominalis ?

According to the taxonomy we are following here (see comments under that photo I linked to above), Melanolestes picipes is the valid species, and Melanolestes abdominalis is just a color form of Melanolestes picipes.

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I appreciate everyones input.

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