We had the same problem (especially with missing PECL extensions), and came up with two different solutions, in this order:
- First we've used Zend Server Community Edition, which has the great advantage of shipping with many extensions, and is free. You can download MySQL Community Server separately, and you've got a working MAMP installation.
- Because this was still not perfect (hard to get PEAR working, for example), we now use what proved to be the best solution for us, running a full LAMP stack on a CentOS virtual machine, with the free VirtualBox, and share the web folder between the host computer and the guest.
If you want to be up & ready in minutes, choose the first solution.
If you want to take some time to set up a virtual machine, you will enjoy the best of both worlds: a real LAMP server always available in your machine, and your usual tools on your favourite OS for your daily work. We're now using this solution on both Windows & MacOS, and really enjoy it.