I was thinking about the following some time ago. My question is whether such things have been studied before.
Let $E_n$ be the abelian group with a generator for each (bounded) euclidean polytope of dimension at most $n$ and relations (1) $P=Q$ if $P$ and $Q$ are congruent, (2) $P\cup Q=P+Q-P\cap Q$, (3) $\emptyset=0$.
Clearly the cokernel of the obvious map $E_{n-1}\to E_n$ is the usual $n$-th euclidean scissors congruence group.