Anything is possible, but you will have to do a *lot* of work for this. An oscilloscope-type display is a vector display (X-Y), whereas any computer or TV monitor is a raster display (lines of dots).
Driving an X-Y display for this application is quite easy, just using analogue techniques. Driving a raster would require that you digitise the information, form a full-frame image in memory, then send this in the appropriate format to the monitor. Much more difficult.
Personally, if you really want a monitor display, I would digitise the frequency versus power sweep and pipe it into a PC using USB (or a fast digital input card). Then you can write code to display it nicely.
An alternative - look for a large X-Y display screen, often seen on eBay and quite cheap. These are essentially a bare-bones oscilloscope with just basic defelection circuits. This will give you a much bigger screen than an oscilloscope and you could probably build the SA cicuitry into the display box.
Cheers,
FoxyRick.