Why do you want a scout? Because of the price? Or are you genuinely that small?
The Scout certainly is the bargain in the Alpacka lineup. If it had 5 more tie outs and a seat it would cost $850 like the rest of the regular rafts instead of $525. The seat by itself sells for $50 and you could easily add the missing tie outs ($5 each from Alpacka plus a few dollars in glue), so there shouldn't be a $325 difference....maybe $150.
With that said, you can end up regretting a great deal if the boat simply doesn't fit. I haven't sat in a Scout, but it's gotta be tiny. I'm a slim guy with a 31" inseam (I'm 5'11, 160 lbs) and my Yukon Yak doesn't have any extra space. From my PFD thread, I recall you're a similar size. At first I thought the Yak was maybe a little too small, but having sat in it more I think it's the right size. I'm sure the Alpaca model would be too short for me though and the Scout is a couple inches shorter than that. Unless you have a 26" inseam, your knees are going to be popping up out of the Scout, so a spray deck wouldn't work anyways.
If you're willing to get a little adventurous, you could simply make your own spray deck for a Scout. A non-removable deck wouldn't be that hard. Slap on a big piece material with the right PU glue, cut a hole in it for you, then cut a slit or two and slap velcro in there so you can open/close the deck. Lastly, improve the skirt area by adding some fabric so it comes up your ribs and has bungie cord. You also might want a little floating chamber to prevent puddling on the top, but this is easy too with some heat sealable fabric and an iron.
If you're trying to do this cheaply, ask them for an extended length Scout, if they'll do that. If not, look at used rafts or a Flyteweight raft. The FlyteWater raft looks to be quite durable and it has lots of tie outs for 3.5 lbs. If you're going to make your own spray deck, maybe start with this boat as it would be a larger size.