Yes, the units that have variable capacity are "premuim" machines in the products offered, and the manufacturers of these units are very proud of them. The boasting is inflated and claimed ratings are highlighted by every sales pitch. These things have been around for over a decade now, so the various manufacturers have developed lines of machines that have fancy names to designate the added functionality. There are also a lot of these types of systems on the second hand market and in the salvage industry available for a lot less than retail price.
Not knowing your operating needs, I will be very general in describing what is available. Also, due to your backwards system goal (matching the source instead of the load), you're probably not going to find a manufactured unit that will suit you. The source matching interface is going to be non-existent. It will need to be built by you or someone who serves you.
Ok, so choosing a suitable outdoor unit, you have 2 major criteria to consider: capacity and method of modulation. There are a bazillion different units on the market and they are all classified to serve specific purposes. In the variable capacity domain, there are 4 main types of systems. Take a look at this table drawn up by Emerson:
Using this chart should help you decide which method of modulation to employ to meet your specific purposes.
As you can see, the capacity range begins around 2 or 3 tons. This is because all of the makers of HVAC equipment consider anything smaller a "novelty" item. Minisplit systems are a prime example of this. They don't sell a huge number of these systems compared to the larger capacity machines, and even more so with variable capacity setups.
By capacity, they classify anything 2 to 5 ton as residential and anything over 5 ton as commercial. These 2 classes account for 90 percent or better of the corporate revenue stream. As a result, the small, modulating capacity units are pretty much sold as "what you see is what you get" packages with almost non-existent support except for installation instructions. Even if you buy new, don't expect any help from the store or manufacturers, especially if you aren't an authorized dealer. Even they don't get much help.