Alternative to LPM_ROM needed

In what way do you want different behaviour? If you do things that LPM rom cannot then you run the risk of not inferring ram blocks.

It is very annoying that you cannot use textio to initialise a memory (Xilinx will). Raise a support request with Altera and maybe one day they'll implement it. Any chance you could use a initialisation function to generate the values?

You can also use the "ram_init_file" synthesis attribute to get the memory contents, while also using textio to initialise the ram for simulation:

http://quartushelp.altera.com/11.1/mergedprojects/hdl/vhdl/vhdl_file_dir_ram_init.htm