Now that TI has the AUC and AUP logic families which have no trouble running off a single alkaline or silver-oxide cell, how about adding some sub-1V capable linear parts (opamps, references, comparators) to go with them? (National has the LM10 opamp + buffered ref, and Linear Tech and Maxim have 1V to sub-1V capable comparator ICs, but that's all that I know of for analog parts capable of handling such low voltages.)