welcome to forum Guvna,
I've recently build a baritone scale (about 27 inch scale) lap steel, here is a link to my build diary
http://www.buildyourownguitar.com.au...ead.php?t=6844
ask any questions you have. First thing I'd work out is what hardware you are using and if the tuners will have the post in a vertical or horizontal plane. Work out the scale length (most lap steels are around 22-24 inch scale length) then look at what style pickup and bridge will work. Also you need to work out what fret markers you will use.
Keen to see a pic of the red pine and interested in what you will carve !
Best of luck !
Here's another build diary Bruce has done - he gave me the idea to build one so the shapes are similar
http://www.buildyourownguitar.com.au...highlight=deco