Hello Richard. Yes my earlier reply wasn't intended to be offlist. I have near-zero knowledge about non-Indic languages.
All I can say is that Tamil script has eschewed most consonant cluster ligatures/conjoining forms. As for Devanagari, writing श्रीमान्को (I used ZWNJ) i.o. श्रीमान्को is quite possible with existing technology. The latter would be Sanskrit orthography and former perhaps Hindi, although I wouldn't know why anyone would want to run in the को with the preceding श्रीमान् even in Hindi. And IMO it would be better to clearly define at the outset what you meant by "akshara" in your question to avoid confusions by people replying having a different idea of the meaning of that term. -- Shriramana Sharma ஶ்ரீரமணஶர்மா श्रीरमणशर्मा