When a Newtonian telescope is mounted on an alt-az mount, it is called a Dobsonian after the person (John Dobson) that popularized the design.
The configuration you show in your drawing is most commonly called a "Polar Fork"
This kind of mounting has been used for SCTs for decades.
You can do it, but there are some issues.The most serious is that unless you provide for a tube that rotates, you will very quickly find that the eyepeice will get into positions that will be almost impossible to use.
Another issue is that the bearings will not work properly. The Dob works by distributing the weight evenly over the bearings. In the design you are proposing, the bottom bearings would be "Pinched" because all of the weight would be directed downward. You would need to use some kind of tapered thrust bearing (Like a car axle bearing) to take the asymetric load.
A better option is almost always a GEM.
A GEM can be made to be very low to the ground and this is what you need to make the telescope stable and the eyepiece accessible.
In fact, with a GEM, it can be possible to get the tube lower to the ground than even a Dob mount.
Here is a link that shows a great example... Notice how short the legs are in the picture.
This kind of mounting would make it possible to use even a CG5 for an 8" reflector because the legs are generally the weakest part of the mount.
And you could use simple wood legs made from 2x4s so you don't have to cut up your tripod legs.
And with this kind of arrangment, you don't have to worry about fabricating some kind of drive system. Picture of Newtonian optimized GEM mount