So there's no major issues that would result in getting the top tube horizontal, such ad the seatpost/headtube angle becoming too weird?
You'll have to look at the angles.
The head and seat tube angles will get steeper. The seat tube looks fairly slack, so that shouldn't be a problem. The head tube is 73.... I don't know how that will play with what forks I'm sure someone else could advise better, but a quick google says head tube angles range from 71.5 degrees to 74.5 degrees.
Also I have seen two people with road forks on pomps... they were still alive...
You'll have to look at the angles.
The head and seat tube angles will get steeper. The seat tube looks fairly slack, so that shouldn't be a problem. The head tube is 73.... I don't know how that will play with what forks I'm sure someone else could advise better, but a quick google says head tube angles range from 71.5 degrees to 74.5 degrees.
Also I have seen two people with road forks on pomps... they were still alive...