You need to find a LA quilter willing to custom quilt around the embroidery. Those that told you it is too hard are LAQ that don't know how to do anything but all over design or end to end pantos. There is absolutely no reason embroidery cant be quilted around.
Now, if you are still dead set on getting your own machine, I see you are in Texas. Check out ABM Innova machines. They are made right there in your great state. I have one and can't say enough good things about mine.
For what you describe you would need an absolute minimum of a 12ft frame. For quilting around embroidery, I would not start out with computer guided, unless that is what you really want and you are a whiz at digitizing designs on a computer that will go around your embroidery. Personally, I think you are better off with hand guided. The Innova comes automatically with a laser light but I don't see you getting much use out of it because they are made for pantos and you will need to work from the front of your machine to custom quilt around the embroider, not over it.
I would definitely get a stitch regulator though. The Innova's new lightening stitch is a dream.
Not a salesperson for this brand, just a very happy satisfied customer.