Hello,
Yes, you can install multiple versions on same host, but you must follow many caveats and I won't recommened unless you are well versed with Deployment Engine(DE) , ITNM configuration etc.
Two scenarios:
#1 - Root install, in this case, you must wipe out existing DE - for more info read @ https://www-304.ibm.com/support/docview.wss?uid=swg21395154
Which also means, you can't upgrade existing v4.1 any longer to later fixpacks etc. But in this case, there won't be any fixpacks on v4.1, so you should be fine.
#2 - Non-root Install: Follow same procedure to uninstall DE.
fyi - you can always take a backup of DE registry and based on the active version (for e.g. v4.1 / v4.1.1) you want to upgrade , you can import registry and then kick off upgrade process.
Last but not least, select different $NCHOME path when it comes to v4.1 Vs v4.1.1. Also, during install and configuration, you'll have to choose different ports for broker and configuation if you want to run both versions parallely.
Btw, if you have flexibility, always go with v4.2, as its latest and greatst and has all cool features, for more information , you can look @ https://www.imwuc.org/p/do/sd/sid=3110
Good Luck,
Krishna.