As Bruce said a .40-.46 engine is a good starting point for an RC trainer. As far as brand of engine I use OS, Thunder Tiger, Saitos are real nice, as are YS's, and there are still a lot more brands than that. As long as you brake them in right they all run pretty good, it comes down to what you ant to spend and personal preference.
Sorry, I could not get to scan anything tonight, we had our club meeting and the bull session at the end turned into a marathon event. I just got in the door and it pretty late, have to work in the AM.
I would like to give you one bit of advice as far as a radio goes. That is do not buy a 3 or four channel one get a 6-9 channel radio. Why, you may ask, a multi channel radio can be used for anything from the most basic 3 ch set up to an airplane with flaps, bomb drop, or even a helicopter. The radio is where you spend a lot of money and rather than getting the most basic, then buying another start with a good one. As far as brands here again there are a lot of good ones I use both Hitec, and futaba. Now JR and airtronics make some nice ones, and the new spectrum types are supposed to be the best thing since sliced bread...
So many choices, comes down to money again.
Now with a .40-.60 size engine ball park you can have a Wingspan of 5-6 feet, Fuselage of 4-5 feet and a weight of 3.5 to 7 lbs.
The lighter the plane the better (wing loading) for a trainer, most kits for these size engines run between 4-6 lbs total (that is flying weight) and have wing loading of 14 -20 oz/ft2, that is 14- 20 ounces per square foot of wing area. The lighter planes fly slower but sometimes can have problems with wind.
Often you can pick up Sig lt40, Great planes PT 40, Goldberg falcon on ebay for short money and they are all good trainers. The sig Kadet Senior is another, along with a Telemaster, I could list for hours...
I picked up an lt 40 kit for my wife for $50 on ebay, it is rugged has a big wing and a nice stable trainer. Any of the plans I would send you would have to scaled up and printed by someone who can print 3 foot by 6 foot sheets so it is not like you can print them out on a printer at home, you would have to go to kinkos or a local printer to have the plans output and that can cost you 5 10 buck a sheet and there is usually to sheets per set.