Sounds interesting. Maybe the rules could be amended to make the outer orthagonals rook-free zones.
Standard set of pieces on 10x10 board

With all due respect: do the outer ranks/files really need to be rook-free? If White moves 1. Ra2, couldn't Black move Rj9 and have a similar "advantage"? It would eliminate some of the "conventional wisdom" about endgames, like "a win can't be forced with an a-pawn or an h-pawn versus a lone King". Of course these would be b-pawn and i-pawn, respectively, on the 10x10 board. It would still be true of a-pawns and j-pawns, though. Sounds interesting, though. Especially if it can be done online.
So many times I have wanted to move a knight to a square just off the board to get in that last, needed check.
Excuse me for butting in with my own chess variant ideas, but looking at the castling rule; what if there were a number of one-time-use rules like
just once during a game you could call "extra square" and move that knight off the board.
Or how about just once the queen could move like a knight
Or maybe you could change the diagonal color of a bishop?
Nah, pretty silly.
But I think your 10X10 board idea has merit. Haven't seen this in a long time but I remember seeing checkers being avidly played on an expanded board.
Excuse me for butting in with my own chess variant ideas, but looking at the castling rule; what if there were a number of one-time-use rules like
just once during a game you could call "extra square" and move that knight off the board.
Or how about just once the queen could move like a knight
Or maybe you could change the diagonal color of a bishop?
Nah, pretty silly.
But I think your 10X10 board idea has merit. Haven't seen this in a long time but I remember seeing checkers being avidly played on an expanded board.
Ah here ya go... how about every time you make a capture, you draw a card that has your special rule on it. Nobody else knows what you got till you play it. Huh huh?
I used to program. Once I scripted a web page to display a board of X-by-X squares, user entered his preferred dimensions. Maybe someone could do one up for us.

Small detail,
http://superschaak.nl/indexengels.htm
In this variant 10x10 boards are used, and the rows are numbered z, a, b, c, d, e, f, g, h, i and 0..9. So the extra rows are z to the left, j to the right, and there are a 0th and 9th rank.

If White moves 1. Ra2, couldn't Black move Rj9 and have a similar "advantage"?
Yeah. That actually hadn't occurred to me. ("TheWM" stands for "The Wrong Monkey," not for "The Weltmeister.")

In this variant 10x10 boards are used, and the rows are numbered z, a, b, c, d, e, f, g, h, i and 0..9. So the extra rows are z to the left, j to the right, and there are a 0th and 9th rank.
Thanks, that's better than my suggestion. With z through i and 0 through 9 the starting positions of all the pieces would have the same designation as in standard chess.

It's nice to see some interest in this. I've been talking and writing about this variant for over 2 decades and aroused literally no interest before this. Maybe I've finally mentioned it in the right place.
What is the point of having a larger board if you have no extra pieces? Grand Chess by Christian Freeling uses a 10x10 board where the back ranks are also left (nearly) empty, like in your setup, but there the reason is to make room for the R+N and B+N compounds. My own variant 'ElvenChess' also used this idea (moving King + Rooks to the back rank, so there would be room for 5 new pieces).
When you start with open files, like you do, castling would be pretty pointless, and it would be hard to find a safe place for the King. In ElvenChess you start with 10 Pawns in stead of 8, for that reason.

Stuff and Nonsense!
There is only one standard set on 10x10 board in All the Universe.
This is Waterloo
http://chess-checkers-go.blogspot.com/2014/11/waterloo-2edition.html
Has anyone played this variant? If not, would anyone like to, and if so, is it do-able online? I've only imagined it, but it interests me. 10x10 board, standard chess pieces, White's pieces start on b2-i2, White's Pawns on b3-i3, Black's pieces on b9-i9 and Black's pawns on b8-i8. In other words, at the beginning of the game there's an empty row of squares to the left, to the right and behind each player's pieces. The number of possible opening moves would be somewhat greater than in standard chess. A possible drawback: White moving 1.Ra2 or 1.Rj2 might give White an immediate insurmountable advantage, making for lopsided games.