I agree with Fred. The main question is how much cross cut capacity you ‘need’. Cross cuts are mostly a function of the slides (or blade size if fixed). The other being max depth needed, which is more related to the blade size itself.
A good fixed 12" saw can be inexpensive, relatively compact (especially front to back, the dimensions you’re looking to keep small), and offer cross cut capacity similar to most 7 1/4" slide saws. In general, most fixed 12" saws can cross cut around 7 1/2" actual (so, like a 2x8). Small sliders can usually do an inch or so more than that.
As far as rail designs, the innovations haven’t trickled down to many mid range options yet. Makita does have a new ‘side slide’ corded saw (which is also 10" iirc), but it’s not exactly cheap. Milwaukee has a 10" M18 cordless saw with the rails under the table, but it’s pretty expensive. Dewalt makes a compact 7 1/4" cordless saw that continues to fall in price, but the slides are traditional. With that said, it’s still a very small saw overall. Ryobi has a similarly sized option as well, but with that you’re quickly getting into a similar situation to what you currently own.
So it comes back to what capacity you need. Having a high capacity sliding saw that fits tightly against a wall in some sort of miter station is attractive, but there really aren’t a lot of inexpensive options for that just yet.
As far as price of a non-traditional slider, I can’t think of any that beat the new Hitachi you posted, but like mentioned…nothing is really known about it yet user wise.