Starting with a Swank server for Python, I’ve made one for uLisp.
Using this you can use slime-mode in GNU Emacs to interact with uLisp running on a board. The inferior-lisp buffer/REPL is supported, giving you the full emacs experience for a REPL.
Also supported are slime’s eval commands. E.g. slime-eval-last-expression (C-x C-e) which sends the expression to the left of the point to uLisp and displays the result in the echo area at the bottom of the Emacs window.
This is very much a work in progress but the basic functionality is very useful.