Well, as you stated, there is the getKey command which will allow you to poll the keyboard for a keypress. If you want to do it like on the ti-85 and ti-86, you will want the menus at the bottom of the homescreen. You
could make something similar (like a slow and messy clone) by simply displaying the options and then using the getKey command to figure out what key was pressed. If you want a good example of this in action, you can take a look at
ohernandez's Pertiodic table program. It is written in Hybrid-basic so if you aren't familiar with that, the code might look a bit strange, but IIRC, the part where he does the little menu thing is essentially pure basic. It is completely aesthetic though so it is up to you to decide if the slower speed, larger amount of work and bigger code is worth the change from the Menu() command. This makes me wonder, are you doing this to port an old program to a newer calc and want it to look as similar as possible to the original?
tl;dr, it is not possible to easily make menus appear on the bottom like on older models, but you can make a patchy solution with a bit of elbow grease.
EDIT: Here is some commented code to make such a menu
Code: ClrHome //clear the screen
Output(10,1,"OPT1 OPT2 OPT3 OPT4 OPT5 //display the menu options at the bottom of the screen
Repeat max(K=10+cumSum(binomcdf(4,0 //loop that will end when one of the top 5 keys are pressed
getKey→K
End
If K=11 //going to the right label depending on what key was pressed
Goto 1
If K=12
Goto 2
If K=13
Goto 3
If K=14
Goto 4
If K=15
Goto 5
Of course, this code could be modified slightly to do things like draw this menu on the graphscreen instead of the homescreen, or maybe add some lines around the options to make little boxes. 
