A couple of hard-working devs over at TabletRoms have been able to squeeze a custom Ice Cream Sandwich/Android 4.0.3 ROM on to the Dell Streak7. Of course they have the usual disclaimer's about being careful not to brick your system. The ROM isn't 100% complete yet, but works pretty well for the most part. They even included a handy breakdown of what works and what doesn't:

What works:
Wifi
gapps (mostly)
audio
touchscreen
overclocking
superuser
rotation sensors
Screenshots (Press Power + Volume-)
capacitive buttons (home, back, menu)
Video Acceleration
USB Mount
External Storage

What doesn't:

some lag
3g/4g/gsm radio
camera
Bluetooth (until I check with DJ_Steve)
GPS
It's great work, so head over to their thread at the source link below to give them some props when you get the chance, as well as read their instructions. Here's a download link for the ROM: Beta3 - ICS-B3.zip

Source: TabletRoms