As JJ suggested, you might want to look at pellet cookers. They're versatile enough to both smoke and grill. Price range starts out at less than $500 for entry level cookers. My Rec Tec cost right at $1K, and I've been very happy with it...both for grilling and for smoking.
Or you might consider going with one of Weber's many options. A Weber kettle is capable of both smoking and grilling, and many guys use their WSMs for both as well. And all Weber products are very well made...I don't know anyone who owns a Weber that's unhappy with it.
I don't have direct knowledge of them myself, but I've read enough poor reviews of those gas/charcoal hybrid smoker-grill combos, like the Chargriller Duo you mentioned, that I'd probably stay clear of those if it was me. They don't seem to be very well made. If any owners of these rigs disagree, by all means weigh in here and correct me.
Good luck! Half the fun is looking and shopping for a new toy...