I'm using Excel as Access database frontend in few projects. The reason is that the bureau where I'm working doesn't allow installing any applications to workstations, and Access is not normally installed to the workstation.
I'm using VBA, Excel forms and DAO 3.6. It's not very useful for large data mass or large amount of users, but as small office-level applications where only few records are updated/inserted at one time, it is sufficient (under 5 users, thousands of rows, LAN). If big INSERT queries are made, then the action slows down. Large SELECT queries are done quite quickly, 10000 rows takes about 1-2 seconds (from one table).
This solution allows many users to use the database at the same time (unlike Excel itself), and _no_ Access license is needed.
The hard part is to program all the functionality and SQL statements into VBA code. It requires some testing too, of course. If you're familiar to VB coding and SQL, it should be quite easy. Just be sure to turn on the DAO 3.6 objects from VB editor: Tools -> References -> DAO 3.6.
JN