I wouldn't follow the post regarding the use of smokes within a space that is outside of spec for the installation requirements, even with the units programmed as local units....huge no-no and if something happens, your insurer will have a field day, as what equates to a known design flaw, with mounting location and response is the end result. An alarm that falses all the time due to misinstallation is just as bad, if not worse, than no alarm at all.
If you're installing items within a space subject to enviromental concerns, such as a generator enclosure or garage, install a heat detector and monitor that separately, but program it as a responding fire zone. Is specific hazards are known and even a standard heat is not appropriate, an item such as a linear heat detector (protectawire) can be used.
GE makes some "nice" looking units, however they are a pain to service and work on IMHO. Given the choice, I'd go System Sensor or DS (Bosch now) because of their wiring and mounting design vs. GE's. The 449's are extremely dated and lacking a lot of the benefits of the engineering that has come since they were first designed, almost 30 years since the original 400's (445's) but to each their own.
If price were no object, I'd suggest looking at some of the smaller addressable panels that support 25 devices, then integrate with a host panel. Wiring multiple 4 wire fire zones, even with proper EOL supervision relays, will cause all sorts of grief when performing a fire reset, making all your fire zones go into trouble at the same time, unless creative programming is done on the host panel.