Hi Anthony
I'm working from memory and, as I'm not too familiar with the modern Prochem range, you'll need to check on my knowledge.
The Prochem Steempro 2000 range had upto two x 3 stage vacuum motors mounted in series. A colleague had the motors in his Steempro upgraded to a higher spec, so this suggests that there are different motors available.
The Cherokee is an older machine and I can't remember if this was the one with two stage or three stage vacuums, again mounted in series.
With series mounted vacs, it's the "front" motor that has the shortest life as it's working at max rpm for 100% of the time. The second or "rear" motor is the one that changes rpm/pitch during use and tends to have a longer service life.
I wouldn't recommend transfering a vac from one machine to the other as you will loose your back-up machine. But, if circumstances dictate that you must do this, you'll need to check the specs of the motor. In the absence of details, presuming they are all the same manufacturer, Amteck/Lamb, the transfered motor must have the same dimensions for the fan cannister (ie 2 stage or 3 stage and 5.7" diameter (likely) or 7.2" diameter (unlikely)) and the measured height of the motor section needs to be the same (this will relate to the motor power, eg 1200 or 1400 watts). If the motor/vacs are not identical, I would not advise changing one for the other as their will be an imbalance.
What do you mean by a smaller machine? If you are looking for a small physical size but with a similar performance to your Steempro, I like the Alltec Aqua 40. It has small dimensions but in it's highest spec will perform above it's weight.
If you are looking for a spotting machine, I like the Cross American Mitey One Hybrid Turbo. It is a three in one machine that can be used as a spotter, a small back-up machine capable of cleaning a whole room, or as an in-line vac booster to give you more cfm's.
For a dedicated spotter, the Prochem option is a solid performer.
Obviously, there are many other worthwhile machine options available.
As for leasing, I have always preferred an outright purchase financed from savings, a personal loan or a small business loan. It may be wise to consult your accountant over which option will be best for your own particular needs. My concerns about leasing for a one-man business is the repayments should you fall ill, have an accident or loose your driving license. With a purchasing finance deal (but not HP) you can always sell the equipment should the brown stuff hit the fan. Many years ago, a local carpet retailer lost his license for drink-driving. His Jag was parked on his drive for a year but he couldn't get out of the agreement so had to keep up the lease payments. Ouch
Safe and happy cleaning
The Ken