maps4gps, while I am not sure this is relevant here is what I came up with running Adam_e quad, I split into 2 sections (which I think is .5x.5, correct me if I am wrong) I have everything set to compile alphabetically. so its not the Robinson Mount you did.
Command closed before I could copy, but the mp file containing all data (water, transport, gnis, contours ect.) run time was approx 3.15 hours, original file .mp size = 230 megs output= 4.5 meg.
On a side note, I can open the quad described above (Mount Baker, shape file is 956 megs) with no problems in both Global mapper, and Mapwell.
I fully admit Global Mapper is far easier, I may have made a error in going the route I did looking at you process times.
Cheers!