I would start with something like this:
https://www.projectorcentral.com/Epson-PowerLite_1781W.htm

The Epson 3LCD layout tends to provide better color brightness and Epson tends to be more honest about their lumen rating than the competition. LCD color brightness is a major factor in LCD advertising.

These are also a much slimmer design than your previous models which should make transporting them a fair bit easier.

For a bit more zing in the presentation, they also have a higher resolution model of the same thing...
https://www.projectorcentral.com/Epson-PowerLite_1795F.htm

To really get more, I think you have to go from that size up to the 6-10 pound range of models (twice the weight at least!) and in DLP I would look for 5,000+ lumen models and for LCD I would go up at least to 4,000 lumens or higher for a solid bump up in brightness.

https://www.projectorcentral.com/projectors.cfm?g=1&hide=0&st=1&exp1=1&r=&br=4000&br=8000&c=&w=6-10&db=&ar=Wide+%2816%3A9-10%29&zr=&wt=<g=&ll=&wr=&dt=&mfg=&p=&t=&pjl=0&pjw=0&pjh=0&td=&is=&i=d&tr=&tr2=&exp5=1&oop=1&sort=pop&sz=15#top