It would be much easier to manage large report views if (instead of having to have an erroneous amount of columns using sharecol=true), you could put HTML into the valueexpression property.
valueformat=HTML
valueexpression=IF(ISBLANK({somefield}),"<b style='color #FFF; background: #F00;'>NO VALUE!</b>", "<em style='color: 0F0;'>ENTERED</em>")
Right now, that will escape all the HTML and print it as text, but it seems like a strange restriction since HTML in the value property is rendered out.
