I'm renovating and will have to move my main electrical entrance 5 feet from 1st floor to
Basement.
1. I know my service entrance will have to move with a longer feed from the pole
2. Is there a junction box available for ~10 circuits to be extended from
The old location to the new location? Otherwise; it could require rewiring...
3. Is it code legal to sheet rock over this junction box eliminating access?
4. If not #3; is it code legal to install this junction box on the outside wall?

My answers and comments follow your questions:

1. I know my service entrance will have to move with a longer feed from the pole.

So, are you just relocating the panel? If the panel will be farther with a longer feeder from the meter, the meter may need to have a Main Disconnect located at the meter also. A panel that contains the main breaker must be as close to the entrance to the building as possible. There is a unwritten general rule that allows for 10 feet of feeder cable allowed for point of entry to the main breaker.

The issue is the feeder cable before a Main Breaker is considered as unprotected, any short will not trip any fuse or breaker, as there are none. So caution is needed to keep this cable as short as possible.

From the Main Breaker, 4 wire cable must be used to feed any panel. The neutral and equipment ground become separated beyond the Main.

2. Is there a junction box available for ~10 circuits to be extended from
the old location to the new location? Otherwise; it could require rewiring...

There are junction boxes of any size available. For 10 circuits, a 12" x 12" x 6" should be just the right size.

3. Is it code legal to sheet rock over this junction box eliminating access?

No, it is never allowed to bury a junction box. The cover must always be accessible.

4. If not #3; is it code legal to install this junction box on the outside wall?

Sure, a JB can be mounted on an exterior wall. If inside, it can be a standard box, called NEMA 1. If the box will be outside exposed to the weather, then the box will need to be raintight, called either NEMA 3R or NEMA 4.

I'm renovating and will have to move my main electrical entrance 5 feet from 1st floor to
basement.
1. I know my service entrance will have to move with a longer feed from the pole
2. Is there a junction box available for ~10 circuits to be extended from
the old location to the new location? Otherwise; it could require rewiring...
3. Is it code legal to sheet rock over this junction box eliminating access?
4. If not #3; is it code legal to install this junction box on the outside wall?
tkrussell;

Thanks for your quick response and recommendations

Most helpful