Certainly you can. If your a Hammerhead Shark, with eyes on each side of your head.
No, really now; conventional wisdom has always dictated that at least a 1.8:1 ratio, Seating distance to Screen width be observed. This was due to several factors.
Brightness level at screen's center
.......and comfortable viewing at the peripheral edges of one's vision. (no Head twisting)
At 6' from a 10' wide screen, issues arise. Resolution can be aced. But unless you have a truly "pixel-less" image from your PJ, even a 1080p unit will show some image structure.
The width of the screen will fill your vision, and probably not exceed the peripheral edges of your viewing cone. But side-to-side eye movement will HAVE to be a part of your experience. Constantly. Your eyes WILL tend to focus on the center of the screen, and to see content at the sides, either a slight twisting of the head or a sideways roll of the eyes will be required. It can be something you do not seem to notice, but it will wear you out over 2-3 hours, and for most, give you considerable eye strain and potential headaches.
Also, a 120" screen, if not 4:3 in nature, you screen is 59" tall (just under 5') Given that you'd at least mount such a screen at 24' off the floor, that places the top of the screen at 7'. That's at least 3' above your level of eyesight as you stare straight ahead. If you recline to see better, you'll be watching movies between your toes. But immersed in the content you will be.
IF it's a 4:3 screen, it just get's worse "Height wise" (....or better if your a masochist
) because such a size screen is 6' high. Your gonna be craning your neck to watch. But the width is reduced to 8'.
The Elunevision screen a few posts above is 134". Thats 80" x 107", both well under 13' yet he states his experience is "just like being at the movies". He's at about a 1.2:1 ratio
I'm an advocate for being able to suggest a 1:1 ratio, and do so almost all the time. 1.2:1 at most. But I use screens with completely smooth surfaces, and PJ that excel at delivering nearly smooth, or completely smooth, pixel-free images. But I know the limitations for practical viewing for extended periods of time, and the best image "in your face" will wear down the most ardent advocate of "HUGE".
But some do not follow such advice, opting for wall sized imagery if at all obtainable. To each his own, but to those individuals, a quick web search for a local Opthmologist is also recommended.